I would say far too often!  I have seen far too many good looking web sites that have almost none of the Meta information that Google and others use to help determine what the web site is about and its importance. Sure, I know that the content or information in the website is one of the most important factors but we should not discount the presence of title tags, description meta tags or h1-4 tags. We know that Google uses some 200 different variables about a web page and web site to determine which ones to present to searchers.

Because most people don’t even know that these things exist we leave it up to the ‘webmaster’ or IT Guy to fill in this important marketing information.

At best these fields get filled in by the best guess of the guy putting the web site together and frequently are just left blank.

Another very common mistake is to write the content for a web site without regard to marketing. The content is written by a specialist in the particular service or product being described instead of someone who is marketing that product on the web. Some one in the whole process needs to act as the Web Marketer and address these very important concerns.